The negative portrayal of Africa in the eyes of the British public is undermining efforts to bring an end to hunger on the continent, Oxfam has said.

The aid agency said that three-fifths of people questioned said they have become desensitized to images depicting issues such as hunger, drought and disease.

Although nearly three-quarters (74%) of respondents thought it was ultimately possible to bring an end to hunger across the continent, only one in five believed they could play an active role in this.

When asked to select what they thought were the three most pressing problems facing Africa over the next year, almost half (47%) of the more than 2,000 people surveyed by YouGov identified hunger.

Over-exposure to negative media and advertising portrayals of Africa and developing countries in other parts of the world was described as "depressing, manipulative and hopeless" by respondents.

And almost half (43%) said it made them feel that conditions for people living in the developing world would never improve.

In response, Oxfam is launching a new campaign to try to refocus public support for the cause.

Through the Food for All campaign, the charity aims to show the continent's potential instead of just its problems by striking a more optimistic tone.

Oxfam chief executive, Barbara Stocking, said: "Oxfam has led the way in drawing attention to the plight of Africa's most vulnerable people and we aren't trying to gloss over the problems that still beset so many of them, particularly levels of malnutrition that remain stubbornly high.

"But we've come a long way since the 1980s and Band Aid's Do They Know it's Christmas? We need to shrug off the old stereotypes and celebrate the continent's diversity and complexity, which is what we are attempting with this campaign.

"The relentless focus on ongoing problems at the expense of a more nuanced portrait of the continent, is obscuring the progress that is being made towards a more secure and prosperous future.

"If we want people to help fight hunger we have to give them grounds for hope by showing the potential of countries across Africa; it's a natural instinct to turn away from suffering when you feel you can do nothing to alleviate it."

In another recent Oxfam poll, when asked to name the first thing that springs to mind when thinking of Africa, more than half (55%) of 1,295 respondents spontaneously mentioned issues relating to hunger, famine or poverty.